On a day when Bees keeper Simon Moore had been a virtual spectator, Brentford created chance after chance but just could not break the deadlock.

That was until Saunders was brought down in the box in time added on at the end of the 90 to snatch all three points.

Earlier, Clayton Donaldson's shot from 35 yards out took a wicked deflection and was looping into the top corner before visiting keeper Declan Rudd pulled off a flying save, and when the resulting corner was only cleared as far as Harlee Dean, the Brentford defender had Rudd scrambling across his goal again to keep out a low drive.

Donaldson then stung the hands of Rudd again from a similar area from which he scored Tuesday night's winner against Swindon, after being put in by Sam Saunders, whose bobbling effort from outside the area a few minutes later was pushed around the post by the busy Preston custodian.

Lee Holmes then blasted over for Preston, while at the other end, it twice took Rudd diving at the feet of Tom Adeyemi to stop the Brentford man being clear through on goal.

But the hosts came closest to taking the lead on 36 minutes when Dean's header from a corner had Rudd beaten all ends up and was heading for the top corner until David Buchanan headed off the line.

Preston could easily have, however, gone straight down the other ends and scored, but Jack King wastefully side-footed wide when found unmarked in the area from Stuart Beavon's pull-back.

Saunders put a pearler from the edge of the area just wide as half-time approached, but the game finished goalless at the break.

The Bees started the second half as they finished the first, on the attack, with Toumani Diagouraga's goal-bound belter headed clear by Keith Keane, while Bradley Wright-Phillips was inches away from breaking his Brentford duck from Adeyemi's inch-perfect pass.

Jonathan Douglas should have done better than putting the ball over the Ealing Road roof after Rudd failed to deal with a floated cross from Saunders, whose free-kick was then tipped over by Rudd as it headed for the top corner.

As Brentford started to get desperate, sub Marcello Trotta was booked for as dive in the area before failing to get anything on an inviting cross from Shaleum Logan, while Saunders fired wide with the goal at his mercy from another Logan ball in.

But in injury time, salvation arrived when Saunders was bundled over in the box before picking himself up to smash the penalty home.